You Dirty Brother Killer
by Sylphie3000
Summary: Underswap AU, Genocide run. Frisk goes to meet their match (and then some).
Frisk's first impression of the hall was that it was rather unassuming, once this body got past the shock of cold and actual _daylight_. For something that should have been grandiose, it was really rather small in comparison with the towering caverns and tapering stalactites of the rest of the Underground.

And rather yellow.

Frisk _hated_ that color. No, seriously, _fuck_ yellow. The petals of the flowers their body had been buried under still bled into their vision every time this body closed it's eyes. If Frisk never had to see yellow again, it would be a God damn blessing.

One SAVE later, and Frisk shoved their body, in a slow, misleading shamble down the hall. They clutched their knife tighter as they approached the end, where the pillars were built so much closer together-some sort of structural instability, or something. Whatever the reason, the body's heart sped and Frisk's soul matched it beat for beat. The lips curled into a slow, malicious smile carving up one side of the dust-stained face and the feet moved faster despite the protestations of the other... _thing_ inside.

 _Frisk, I swear to everything I hold dear, if you don't turn back now_ , Chara threatened, the mental voice angry and very, _very_ afraid. Chara's fear fueled the body's apprehension, but when adrenaline rushes reflexes are faster.

All the better for what happens next, Frisk supposed.

 _What are you gonna do?_ They threatened, and a husky, ragged laugh spread throughout the hall. _This body, this world...these monsters. Mine. All of it. You can't so much as control your own_ eyes _anymore. So, tell me, Chara: what are you going to do?_

Chara's voice did not respond, but their fear pulsed throughout the body in shakes and waves-ecstasy to Frisk, crippling to the other. Together, though not at all willingly, they shambled down the corridor.

At the end of the hall, where the three columns stood on either side in rapid succession, he appeared. First was a puff of smoke, then the cherry of a cigarette, followed soon by the face and bright orange hoodie Chara and Frisk knew well, out of the shadow of a pillar. Not from behind the column itself, but _out of the shadow_. One moment the only living thing inside had been the body, the next…

Papyrus.

The skeleton stood tall, and could have stood several inches taller had he not been slouching, but even so, combined with the faux-relaxed posture he bore like a shield, he made an intimidating figure.

"I was wondering when you would show up," he said, throwing back his head in a lazy circle to look at the ceiling. Smoke curled around his head from the inside; from this angle, Frisk could see the butt of it, could see the smoke weave out from his nasal cavity, the bottom of his jaw-hell, even from his _eyes_.

Frisk said nothing. Papyrus didn't look like he expected a response.

"You've been kinda busy, yeah? I mean, that _mess_ you left back there… well, let's just say there's only _one person left_ to clean it up, and thanks to _you_ it's gonna take a while. I think I could use a bit of help, really, or even an apology." Papyrus rolled his head back down as he spoke, and though he didn't change his posture the air around him seemed to drop several degrees-or maybe that was just the body's response to the intense amounts of panic pouring out of Chara.

 _Calm yourself_ , Frisk told them. _You can't do anything to change it, and you're distracting me. We don't want this body to get_ hurt _, do we?_

 _Frisk, please don't do it-please don't hurt him, you already got S-Sans, just leave him,_ please _Frisk, oh God_ -

 _Shut up._

Chara obeyed only somewhat- their nagging whimpers and begging, as annoying as they were, stayed tucked back in a corner of Frisk's mind. Constant, but quiet, as always. _Good_.

"Really, kid?" Papyrus continued, unaware of the battle going on behind that tiny, dust streaked face. "Not even an _apology_? For… well, I didn't expect _much_ , but you didn't even _threaten_ me."

The shadows on the floor shifted with the rising sun. Engulfed in shade, Frisk's shared body dropped several degrees more in temperature. The hand clutching the knife was the only one warm-the other, hanging limply at rest, was completely numb.

"No, you know what, kid-human-whatever the _hell_ you are," the skeleton growled, voice slipping several octaves as blue magic flashed in his right eye socket. "You're joining the masses out there, but the likes of _you_ aren't getting touched. You're going to stay here, rotting on this floor, until all that's left is whatever humans have underneath that skin of yours."

Frisk's soul was drawn out through the chest, from the place Chara's should have been (had every _right to be_ ), and enveloped their body in a red to match the end of Papyrus' cigarette. The room darkened, for real this time, as the encounter blocked out most of the sun's light.

Outside, for the first time since Frisk could remember, birds whistled. Their hand tightened on their knife.

"Do you hear that?" Papyrus' voice sounded much closer in the magical confines of the encounter than it had echoing through the hall. "Birds are singing. Somewhere, flowers are blooming. On days like these, kids like you…"

The cigarette fell to the floor. Papyrus stepped in it and took in a whiff of air as the last of the smoke wreathed itself around his head.

"You're not even a kid, are you? Well, whatever you are…" Blue magic, to contrast Frisk's red, sprung to life throughout the room. "You're gonna be dead, you dirty brother killer."

 **A/N: Hey guys, here I am in Undertale/Underswap hell. Yay! It's... well, I got dunked on by the other skelebro today, and immediately watched an Underswap thing, so that's where this came from. Hooray!**


End file.
